Cartridge case



G. C. POTTS CARTRIDGE CASE March I, 1966 Filed March 4, 1964 INVENTOR.

GEORGE C. POTTS A QBNEY United States Patent Ofiice 3,237,561 Patented Mar. 1, 1966 3,237,561 CARTRIDGE CASE George C. Potts, Philadelphia, Pa., assignor to the United States of America as represented by the Secretary of the Army Filed Mar. 4, 1964, Ser. No. 349,507 3 Claims. (Cl. 102-43) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to metallic containers and, more particularly, to such containers employed as cartridge cases which are subjected to high pressures when used in gun chambers or with other propellant actuated devices.

One of the objects of the invention is to provide a cartridge case which has the maximum capability of sealingly withstanding high pressures at critical areas thereof, while permitting its sidewalls to expand circumferentially and subsequently contract with a maximum degree of flexibility for a given design.

Another object of the invention is to provide such a cartridge case having a single wrap sidewall construction formed of a minimum amount and corresponding weight of material.

A further object of the invention is to provide such a cartridge case which will facilitate a moisture proofing operation thereon, and also which can be readily withdrawn when desired from its operational environment.

These and other objects, features and advantages of the invention will become apparent from the following description and accompanying drawings in which:

FIG. 1 is a top plan view of a sheet metal blank from which are formed the cartridge sidewalls in a preferred embodiment of the invention;

FIG. 2 is a similar view of the sheet metal body after predetermined flaps have been folded;

FIG. 3 is a longitudinal sectional view of the assembled cartridge case; and

FIG. 4 is a partial sectional view of the cartridge sidewall portion taken along line 44 of FIG. 3.

The sheet metal blank (FIG. 1) is formed, by apparatus (not shown), with one marginal end portion 11 provided with an extension 12 adapted to be reversely bent about a transverse fold line 13, and with opposed longitudinal marginal edges 14, 15 each provided with a respective flap or extension portion 16, 17 adapted to be reversely bent about a respective longitudinal fold line 18, 19. After the blank 10 has been formed, the flaps or extensions are reversely bent about their fold lines by means (not shown). As seen in FIG. 2, flaps 12 and 16 are formed as reverse bends on one side (inside surface) of the blank, whereas flap 17 is bent in the opposite direction to form a reverse bend on the other or outside surface of the blank 10.

With the blank formed as shown in FIG. 2, the longitudinally extending return bends 16, 17 are interlocked (FIG. 4) with each other to form a rolled and single wrapped cylinder 24 (FIG. 3), the one end of which containing return bend 12 is to be secured to a base member 25, as will be discussed hereinafter. The marginal edge 15 is formed as an inwardly directed offset about longitudinal line 20 by appropriate means (not shown). The extent of the inwardly directed offset marginal edge 15 from its adjacent main body portion 21 is such as to exceed slightly 3 times the thickness of the sheet metal blank material, permitting return bends 16, 17 to be simultaneously positioned in a respective one of opposed longitudinally extending lateral or circumferential pockets 22, 23 formed by the other return bend and its marginal edge. The lateral extent of each return bend 16, 17 is less than that of offset edge 15, so that the base of each pocket presents a void under normal pressure conditions wherein outer surfaces of portion 21 and edge 14 may form a substantially smooth or true cylindrical lateral or peripheral surface. The longitudinal voids or pocket bases form a means for allowing expansion and contraction of the cylindrical body under operational internal pressure deviations when the return bends slide to varying positions within their respective pockets.

The single-wrapped cylinder 24 is thus closed by the single, straight seam that extends substantially the full length of the cylinder, and the extremities of its one marginal end 11 containing reverse bend 12 is spun inwardly on a mandrel (not shown) and subsequently secured to base member 25. Preferably, the base 25 is provided with a predetermined passageway 26 for receiving an ignition means and has a substantially transverse planar inner surface 27. Adjacent the outer periphery of surface 27, preferably a pair of concentric annular recesses 28, 29 are provided in surface 27, recess 29 being relatively innermost or more centrally positioned and having a somewhat dovetail configuration.

Collar 30, formed as a metallic ring or annulus and having substantially the same radial dimensions as the dovetail recess 29, is provided with a bifurcated leg or base portion 31 for insertion within recess 29 and an upstanding leg portion 32. The inwardly spun extremities of the return bend 12 and its marginal end 11 are sealingly clamped between an edge of ring leg 32 and recess 28 by apparatus (not shown) as the bifurcated ring base 31 is spread to substantially fill dovetail recess 29. It is apparent that pressurized gases that tend to enter between return bend laminations 11, 12 are substantially retarded from leaking and possibly destroying the gun chamber or other environment for cartridge case or cylinder 24.

Variations and modifications may be resorted to without departing from the scope of the invention as defined by the appended claims.

I claim:

1. A cartridge case for propellant use comprising,

a base member having a substantially circular peripheral portion and a substantially planar transverse surface extending inwardly of said peripheral portion, said transverse surface having a dovetail shaped annular recess;

a substantially cylindrical sheet metal body having one marginal end portion formed with a reverse or return bend extending inwardly of and juxtapositioned to said marginal end portion;

means solely on said body sealingly interlocking opposed longitudinal marginal edges of said cylindrical body, said means including an inwardly directed return bend formed along one of said edges with a longitudinal pocket therebetween, an inwardly directed offset provided as the other marginal edge and having an outwardly directed return bend therealong with a longitudinal pocket therebetween, each of said marginal edge return bends extending substantially the full length of said cylinder into the pocket of the other marginal edge with a lateral extent less than that of said offset; and

means sealingly securing the outermost extremity of said marginal end portion and its corresponding return bend portion to said base member adjacent the periphery of said transverse surface, said securing 3,237,561 3 4 means including a collar having a bifurcated leg References Cited by the Examiner portion engaged within and substantially filling said UNITED STATES PATENTS recess and a ring leg in engagement with the return bend of said marginal end portion; g g yfi l043 so constructed and arranged that voids may be formed 5 495857 /1893 O b h 105-213 along the base of s id pockets under normal pressure 980,351 1/1911 fi ug %82 4: conditions Which l allow for expansion and 'con- 1 038,007 9/1912 $113223 1O2:44 traction of Said y nder operational pressure 28231611 2/1958 Thayer 102 44 deviations. I p g 2. A cartridge case as set forth in claim 1 wherein the v 10 FOREIGN PATENTS offset extends inwardly of an adjacent peripheral cylindrical body portion a distance approximating 3 times the 6/1957 ythickness of said Sheet metal 'i BENJAMIN A. BORCHELTQPrimary Examiner.

3. A cartridge case as defined in claim 1 1n which said 15 SAMUEL FEINBERG, Examiner.

cylindrical sheet metal body has a substantially single wrapped sidewall construction. R. F. STAHL, Assistant'Examiner. 

1. A CARTRIDGE CASE FOR PROPELLANT USE COMPRISING, A BASE MEMBER HAVING A SUBSTANTIALLY CIRCULAR PERIPHERAL PORTION AND A SUBSTANTIALLY PLANAR TRAVERSE SURFACE EXTENDING INWARDLY OF SAID PERIPHERAL PORTION, SAID TRANSVERSE SURFACE HAVING A DOVETAIL SHAPED ANNULAR RECESS; A SUBSTANTIALLY CYLINDRICAL SHEET METAL BODY HAVING ONE MARGINAL END PORTION FORMED WITH A REVERSE OR RETURN BEND EXTENDING INWARDLY OF AN JUXTAPOSITIONED TO SAID MARGINAL END PORTION; MEANS SOLELY ON SAID BODY SEALINGLY INTERLOCKING OPPOSED LONGITUDINAL MARGINAL EDGES OF SAID CYLINDRICAL BODY, SAID MEANS INCLUDING AN INWARDLY DIRECTED RETURN BEND FORMED ALONG ONE OF SAID EDGES WITH A LONGITUDINAL POCKET THEREBETWEEN, AN INWARDLY DIRECTED OFFSET PROVIDED AS THE OTHER MARGINAL EDGE AND HAVING AN OUTWARDLY DIRECTED RETURN BEND THEREALONG WITH A LONGITUDINAL POCKET THEREBETWEEN, EACH OF SAID MARGINAL EDGE RETURN BENDS EXTENDING SUBSTANTIALLY THE FULL LENGTH OF SAID CYLINDER INTO THE POCKET OF THE OTHER MARGINAL EDGE WITH A LATERAL EXTENT LESS THAN THAT OF SAID OFFSET; AND MEANS SEALINGLY SECURING THE OUTERMOST EXTREMITY OF SAID MARGINAL END PORTION AND ITS CORRESPONDING RETURN BEND PORTION TO SAID BASE MEMBER ADJACENT THE PERIPHERY OF SAID TRANSVERSE SURFACE, SAID SECURING MEANS INCLUDING A COLLAR HAVING A BIFURCATED LEG PORTION ENGAGED WITHIN AND SUBSTANTIALLY FILLING SAID RECESS AND A RING LEG IN ENGAGEMENT WITH THE RETURN BEND OF SAID MARGINAL END PORTION; SO CONSTRUCTED AND ARRANGED THAT VOIDS MAY BE FORMED ALONG THE BASE OF SAID POCKETS UNDER NORMAL PRESSURE CONDITIONS WHICH WILL ALLOW FOR EXPANSION AND CONTRACTION OF SAID BODY UNDER OPERATIONAL PRESSURE DEVIATIONS. 